What is the essence of this partnership? I never heard about porkbun, but I see it's a domain registrar, so I suppose the point is that now they offer a custom domain for your proton email... but it was always possible to attach a custom domain to proton email (if you pay for it, naturally). So, in what sense they are partnering? Like, it's now cheaper to do with porkbun + proton than porkbun + anything else, or proton + anything else? Basically, is it just some sort of meaningless marketing announcement, or is there more substance?